Note: Descriptions are shown in the official language in which they were submitted.
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Apparatus for launching and landing of boats
The present invention relates to an apparatus for launching and
recovery of a lifeboat, rescue boat or like small boat on a vessel, a
floating platform or a fixed installation such as, for example a
harbour pier. In order to facilitate this description, the expressions
l~boat" and llvessel'l will be principally employed below, it being
understood that the expression '~boat~ encompasses pick-up boats,
lifeboats, rescue boats etc. and that the expression '~vessel~ also
encompasses a platform, pier etc.
One problem in the launching and recovery of boats on vessels is that,
because of the difference in size, the vessel and the boat move
differently in the water. As a result, there will be large relative
movements between the vessel and the boat. In addition, waves are often
built up to a greater height along the side of the vessel than they
would otherwise do, which gives additional large relative movements
between the vessel and the boat.
Today, boats on board vessels are normally suspended in davits with
whose aid the boats are launched in the water. Conventional davits are
primarily intended for launching and function less satisfactorily when
retrieving a boat in a high sea. On some vessels, a crane may be used
for launching and recovery of a boat.
Lifeboats are normally suspended at two points wires operated by the
davit winch. In a number of systems for pick-up boats, a single-point
attachment is employed. When, on launching and recovery of a boat,
hooks are attached or released from the boat, there is a risk that the
generally heavy hooks and blocks connected to them may hit the boat
because of the large relative movement between the vessel and the boat.
Moreover, in systems employing two lifting points, there is the risk
that only one hook is disengaged/engaged, in which event the boat runs
the risk of being left hanging vertically along the side of the vessel,
depending upon what direction the relative vertical movement between
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-
the boat and the vessel takes. Even if the crew is successful in at-
taching or disengaging the hooks from the boat, there is moreover the
risk that wires are slack to such an extent that these hit the boat.
This applies as long as the boat has not been raised free above the
crests of the waves.
If the mother vessel is to be kept under control, it must be under way
somewhat in a forward direction, which entails that the engagement and
disengagement operations as described above must be able to be put into
effect while moving forwards. This makes it even more difficult to exe-
cute a launching or recovery operation of a boat using the conventional
systems.
There is, thus, a need in the art for a system for the launching and
recovery of boats in which the above-outlined drawbacks are obviated or
at least reduced to a minimum.
The present invention comprises an apparatus, here designated a dock,
in which the boat is stored on board a mother vessel, the dock being
floating. The dock is connected to davits or the like and the boat may
be run out of and into the dock when the dock has been lowered to the
floating position.
From publications N0 141 929 and N0 162 184, systems are already previ-
ously known in which boats in a lowered floating position are run into
or out of special apparatuses for recovery and launching, respectively.
These prior art apparatuses suffer, however, from the disadvantage that
they must be lifted a relatively long distance before the boat proper
begins to be lifted. As a result of the large waves which may be built
up along the side of the vessel, the risk is then great that the boat
moves in relation to the apparatus, in which event it may strike
against parts of the apparatus, assume an oblique position inside the
apparatus and capsize when the apparatus is lifted, or that hooks,
lines and the like hit the boat. From the above-mentioned publication
N0 162 184, it is previously known to employ a net for lifting the
boat. This functions satisfactorily as long as the vessel is dead in
the water, but if the vessel is under way or if there is a current, the
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risk is great that the net does not maintain its intended configu-
ration, but behaves roughly like a trawler net. If the net is in the
incorrect position, this naturally causes problems when lifting the
boat.
- 5
One wish is that the floating dock and the boat should have as similar
seakeeping properties as possible, which entails that the boat rela-
tively simply may be run into and out of the dock, since the boat and
the dock will have the same pattern of movement, i.e. the relative
o movement between the dock and the boat is slight. The dock should an-
swer to a wave just as quickly as the boat.
The above needs and wishes are satisfied by an apparatus according to
appended claim 1.
Yet a further wish in systems of this type is that the boat and its as-
sociated dock or the like must rapidly be able to form a unit in order
to minimize the risks of relative movement between dock and boat.
Another wish is that the system should be capable of simple adaptation
to existing vessels. This is achieved in the present invention in that
conventional davit systems may be employed. As a result, only minor
modifications to the mother vessel are normally required. The apparatus
according to the above cited NO 162 184 requires that a special two-
armed crane be used.
Employing the apparatus according to the present invention, it is pos-
sible to handle all types of boats in existence today.
Expedient embodiments of the present invention are disclosed in the ap-
pended subclaims.
When, in the description below, mention is made of the forward portion
of the various parts, this is taken to signify that part which, in nor-
mal use, co-operates with or is located in the forward region of the
boat, and the corresponding situation applies to the rear part and
similar expressions.
...
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,
The present invention will now be described in greater detail here
below, with particular reference to various embodiments shown on the
accompanying drawings. In the accompanying drawings:
Fig. 1 is a side elevation of one embodiment of the present inven-
tion,
Fig. 2 is a top plan view of a modified embodiment of the present
invention,
Fig. 3 is a section taken along the line III-III in Fig. 2,
Fig. 4 is a section taken along the line IV-IV in Fig. 2;
Fig. 5 is a detailed view showing one embodiment of the cradle in
which the boat is received; and
Fig. 6 is a section corresponding to that of Fig. 4 of an alternative
embodiment.
The dock has one or more buoyant elements which support a cradle 2 in-
tended for supporting and carrying a boat 14. The cradle 2 rests in a
frame construction or frame 3, the frame 3 being fixed to the buoyant
elements in a suitable manner.
In the illustrated embodiment, the buoyant elements consist of two
buoyant bodies or pontoons 1 disposed on either side of the frame 3. In
other embodiments (not shown), the buoyant elements consist of a con-
tinuous hull, two or more buoyant bodies on either side of the frame,
etc.
Irrespective of the configuration and number selected, the buoyant ele-
ments must have a total displacement which is sufficient to support the
dock together with a fully loaded boat 14. The buoyant elements must
ensure that the dock (or more precisely the cradle) assumes the correct
floating position so that the boat 14 may simply be run into and out of
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the dock. In addition, the buoyant elements must be of such configura-
~ tion and have such displacement that the dock in its entirety has the
same seakeeping properties as the boat 14. The seakeeping properties,
floating position etc. of the dock are influenced by modifying the
configuration and size of the buoyant elements. The dock must be given
rolling and pitching periods which as closely as possible correspond to
those of the boat in order to achieve similar seakeeping properties. It
is not possible to state the exact configuration and si~e generally,
but these must be arrived at by test for each specific embodiment of
dock and boat 14.
Fenders 5 are disposed on the outer sides of the buoyant elements in
order to damp any possible collisions against the side of the vessels.
The fenders 5 are suitably made displacing, i.e. they constitute a part
of the buoyant elements. One example of suitable fenders is inflated
rubber fenders. The fenders 5 are provided on the outside with a wear
surface, for example rubber.
The cradle 2 disposed in the dock is adapted to the bottom shape of the
boat 14. The boat 14 may be flat-bottomed, round-bottomed with differ-
ent curvatures, or be provided with a keel of different angles, or a
combination of these. In, for example, water-Jet powered boats, the
bottom is flat at the stern but may be rounded further forwards. In the
embodiment shown in Figs. 4 and 5, the cradle 2 is constructed from two
or more transversely placed elements each consisting of a bottom beam
17, two oblique struts 18 and two edge stays 1g. The inclination of the
oblique struts 18 is adapted to the bottom configuration of the boat.
Midway in the cradle 2, there is a set of rollers 10 disposed facing
towards the boat and, on the sides of the oblique struts 18 facing to-
wards the boat 14, one or more sliding strips 11 are disposed. Both thesliding strips 11 and the set of rollers 10 are disposed in the longi-
tudinal direction between the elements consisting of the bottom beam
17, the oblique struts 18 and the edge stays 19. The concept is that
the boat 14 should, if necessary, be capable of sliding on the rollers
10 and the sliding strips 11 when the boat is manoeuvred into or out of
the dock. In Figs. 2 and 3, rollers 10 are shown as disposed for co-
operation with the outer sides of the boat in order to steer the boat
, . ,
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in position. A person skilled in the art will perceive that, in other
embodiments (not shown), use is made exclusively of rollers 10 or ex-
clusively of sliding strips 11 or that the rollers or sliding strips,
respectively, are disposed in other positions as compared with that
shown in the illustrated embodiment. In order to damp the collision
loading against the bottom of the boat on running into the dock, the
cradle too is, in one embodiment, resiliently mounted (Fig. 5) in the
frame 3. The resilient mounting is effected by means of a number of
springs 12, rubber elements or other resilient devices disposed between
the bottom beams 17 of the cradle 2 and the frame construction 3. In
one alternative embodiment (not shown), the cradle 2 is suspended with
resilient elements in the frame construction 3.
In one alternative embodiment, the cradle consists of a net 26 (Fig. 6)
tensioned in the frame 3 by means of springs 27 in such a manner that
the net forms a cradle. In such instance, there are no rollers 10 or
sliding strips 11, but the boat instead slides on the net itself. In
one embodiment, the net consists of glass fibre rods interwoven with
belts or lines of a suitable fibre material, including synthetic fibre
of, for example, polyamide, polyester and aramide.
In further alternative embodiments (not shown) the cradle 2 consists of
a bottom beam on which two or more upstanding posts are disposed. The
posts normally slope somewhat inwards and are provided with rollers or
support sliding strips. A person skilled in the art will perceive that
the cradle 2 may be constructed in many different ways as long as it is
adapted to the configuration of the boat 14.
In the illustrated embodiment, the frame construction 3 includes two or
more tranversely placed elements consisting of a bottom beam 20, two
side beams 21 and a crosspiece 22 which are interconnected to form a
rectangle.
Between these two or more transversely placed frame elements 20-22 at
3~ least one upper interconnection beam 23 and one lower interconnection
beam 25 are disposed longitudinally and connected with the side beams
21. In a number of embodiments, one or more interjacent interconnection
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beams 24 are moreover provided. The side beams 21 of the frame 3 are
fixed to the buoyant bodies 1. A person skilled in the art will per-
ceive that this fixing may be put into effect in a number of different
ways, but given that this feature does not constitute any germane part
- 5 of the present invention, it will not be described in greater detail here.
A person skilled in the art will further perceive that the construction
of the frame 3 may also be varied in many ways, for example in one em-
lo bodiment, the frame 3 consists only of the lower parts as describedabove, and in another embodiment, the cradle 2 forms the lower part of
the frame 3. Furthermore, the side beams may be disposed with an incli-
nation and/or the interconnection beams may be disposed cruciformly. In
a number of embodiments, the upper or interjacent interconnection beams
23, 24 are moreover employed to suspend other details and parts such as
nets, seat places, railings, etc.
In the upper part of the frame 3, anchorages 4 are provided for co-
operation with winch wires 16. Provision of a permanent coupling
between the winch wire 16 and the anchorages 4 eliminates the need for
providing heavy hooks which, in previously employed apparatuses, were
connected to the boat proper and then constituted a hazard for those
persons located in the boat. In order to take up any possible slack in
the wires , the winches which are employed are self-tensioning and/or
so-called heave compensation is employed. As a rule, the heave compen-
sation is based on the concept that the wires run over a spring-loaded
block where the ability to take up slack is determined, int. al. by the
maximum stroke lengths of the springs. As an extra safety provision,
the frame construction 3 is provided, in a number of embodiments, with
a roof (not shown) on which a slack cable can be received. The
anchorages 4 are placed high so as to minimize the risk if the wires
become slack more than the self-tensioning winches and/or heave
compensation is able to take up.
In the forward part of the dock, the buoyant bodies 1 are provided with
stops 7 which are directed inwards. The stops 7 are designed in corre-
spondence with the bow section of the boat 14. The function of the
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stops 7 is to both guide the boat 14 so that it assumes the correct
position in the cradle 2 and to prevent the boat 14 from entering in
too far.
In order to facilitate running into the dock, in a number of embodi-
ments the dock is provided with screens 13 and/or rollers 10 which co-
operate with the outer sides of the boat in order to steer the boat
into the dock.
o In one embodiment, the stops 7 are supplemented by a catchment net 6
placed in the forward part of the dock, the net 6 receiving the prow of
the boat 14. The net is designed and journalled such that the boat is
arrested gently. The catchment net is only employed together with such
boats 14 in which people cannot sit furthest forward in the prow.
The boat 14 and the dock are provided with suitable, co-operating lock-ing devices 9, 15 for fixing the boat 14 to the dock. The locking de-
vices prevent the boat from sliding out uncontrollably from the cradle.
In the illustrated embodiment, the locking devices consist of rotary
hooks 9 disposed on the boat, the hooks co-operating with pins 15 dis-
posed in the buoyant bodies 1. A person skilled in the art will per-
ceive that this locking feature may be provided in various different
ways and that the different co-operating parts may be disposed on many
different points (in many different positions). In the simplest case,
2S the locking devices consist of a rope end and a co-operating bitt or
the like.
In the illustrated embodiment, the cradle 2 is journalled sloping in
the frame 3, where the highest portion of the cradle 2 in relation to
the water surface lies forwards in the dock. In other embodiments, the
cradle 2 does not slope. Further, in certain embodiments, the cradle 2
is rotatably journalled in its forward portion, in which event a lift-
ing device 8 is provided which lifts the rear end of the cradle 2 and,
therewith, the stern of the boat 14, such that the boat 14 wholly or
partly leaves the water and thereby will rest stably in the cradle 2.
In yet a further embodiment, the entire cradle 2 is journalled movably
in the vertical direction, in which the lifting device 8 lifts the en-
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tire cradle 2 and not only its rear portion. The lifting device 8 con-
sists of one or more rams, actuators, etc. driven by compressed air
vessels, hydraulic accumulators or electric batteries. When the catch-
ment net 6 is employed its lines may be directly coupled to the cradle
2 in such a manner that, when the boat 14 is run in and the catchment
net 6 is tensioned, the entire cradle 2 or its rear portion is lifted
and locked in a raised position with the aid of a locking device (not
shown). In this case, the inherent kinetic energy of the boat is thus
utilised for lifting the cradle. The above applies also to those em-
bodiments in which the cradle consists of a net. In a number of embodi-
ments, contact devices are provided in connection with the stops 7, the
contact devices automatically activating the lifting device 8 when the
boat 14 runs against the stops 7.
In addition to the winch wires 16 which come from the davit, the dock
is connected to the mother vessel also by mooring and guide lines (not
shown). On the frame 3, suitable anchorages (not shown) are provided
for the mooring and guide lines . With the aid of the mooring and guide
lines, the boat 14 is held in a suitable position in relation to the
mother vessel and accompanies the mother vessel's possible movement
forwards. The guide and mooring lines are connected to winch devices on
the dock and/or the mother vessel or the guide and mooring lines have
fixed connections on the dock or vessel, respectively, in which event
these lines are of a fixed length.
The dock including the boat 14 and the davit is placed anywhere option-ally on the vessel where it is considered suitable. It is also possible
to place it in the stern, which makes for more reliable and safer
towing.
When the boat 14 is to be launched, the dock is lowered with the aid ofthe winch devices of the davits. When the dock reaches the surface of
the water and is freely floating, in embodiments provided with lifting
devices as described in the foregoing, the boat 14 (or more precisely
the cradle) is first lowered. The locking device 9 is then released,
whereafter the boat 14 slides or backs out of the cradle 2. The buoyant
elements are of a design to enable the cradle 2 to be held in such a
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position that, when the boat 14 has been released, it lies sufficiently
deep in order, if necessary, to allow the boat 14 to reverse out from
the dock. Normally, the boat 14 is in a floating position whereupon it
is moved out of the dock in that the dock accompanies the mother ves-
sel's forward movement. Moreover, the buoyant elements are designedsuch that, when the boat 14 has been wholly run into the dock (i.e. so
far that its prow abuts against the stops 7 and possibly the catchment
net 6), the boat 14 abuts against the dock at at least two points. In
such instance, the boat 14 is supported at least intermittently in at
least at one point of the cradle 2. The short distance between boat 14
and cradle 2 entails that, in the lifting movement proper of the dock,
there will be at most but a slight relative movement between the cradle
2 and the boat 14. The dock is held at the side of the vessel and in a
suitable position with the aid of the mooring and guide lines. Thus,
the dock remains in position and floats or is in attendance in the
water ready to receive the boat 14 when a mission is completed.
By providing the dock with suitable railings and possible seating
places in connection to the buoyant bodies and a net beneath the cradle
(or that the cradle consists of a net), it is possible to employ the
dock alone for retrieving people in distress on board the mother
vessel. These parts can be supported in the interconnection beams 23-25
over the frame 3. The dock may then be hoisted up without the boat
being in position in the dock. This may be employed for transferring
people in distress to the mother vessel at the same time as the boat 14
is used for retrieving or searching for others in distress.
When the boat 14 is once again to be taken on board the vessel, it is
run into the dock. Given that the dock and the boat 14 have almost en-
tirely the same seakeeping properties, thanks to the buoyant elementsof the dock, it is relatively simple to run the boat 14 into the dock
even in a very heavy sea. When the dock is floating in the sea without
the boat, the cradle 2 lies sufficiently deep for the boat 14 to be
able to be run into the dock. At the same time, the cradle 2 does not
lie deeper than that it intermittently supports the bottom of the boat
14 at at least one point when the boat 14 has been run in so that its
prow abuts against the stops 7 and possibly against the catchment net
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6. If necessary, the cradle 2 is pressed down by the boat 14 when it is
run into the dock. Immediately when the boat 14 has made contact with
the stops 7 or the catchment net 6, the boat 14 is locked in position
in the dock with the aid of the locking devices 9. The boat 14 and the
dock thus rapidly form a cohesive unit in that they are in contact at
at least two points and do not run the risk of being jolted against one
another when the dock is lifted up to the vessel. If the dock is pro-
vided with lifting devices 8 for lifting up the boat 14 wholly or part-
ly from the water, these lifting devices 8 are activated (if they have
not already been activated) with the aid of the catchment net 6 or the
contact devices of the stops 7. The next stage is to lift the dock with
the boat 14 in the cradle 2 on board the mother vessel.
The above detailed description has referred to but a limited number of
embodiments of the present invention, but a person skilled in the art
will readily perceive that the present invention encompasses a large
number of embodiments without departing from the scope of the appended
claims.
